Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 106 for “"bubble size"”.
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Texture and bubble size measurements for modelling concentrate grade in flotation froth systems
… the watershed algorithm for the measurement of bubble sixe distribution in flotation froths. Unlike the standard watershed algorithm, it is able to measure accurate bubble size distributions when both large and tiny bubbles are present in a flotation froth image. Flotation froths with “dynamic …
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Bubble Size Effects in Coal Flotation and Phosphate Reverse Flotation using a Pico-nano Bubble Generator
… industry. However, it is effective in a narrow size range, nominally 45--250 mum for coal and 10--150 mum for minerals. And the flotation performance of coal and minerals beyond this size range is not quite satisfactory. It is now recognized that the low-flotation efficiency of ultrafine …
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Investigating the effect of perforation diameter and carbon dioxide bubble size distribution on heavy oil recovery
… the effect of perforation diameter and CO2 bubble size distribution on the viscosity and recovery of heavy oil during Enhanced Oil Recovery process. To conduct the investigation, an experimental rig was constructed to simulate the flow of CO2 in heavy oil. The oil viscosity, CO2 bubble sizes …
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An experimental study on the effect of viscosity on micro-bubble size distribution and rise velocity in a bubble column
… capacities. DAF systems generate microscale air bubbles to lift suspended particles in influent solution to the top of a rectangular tank and remove them by scrapers. Due to the recent focus on different applications of micro and nanoscale air bubbles across many industrial operations, …
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Theoretical and numerical study of air entrainment and bubble size distribution in strong free-surface turbulent flow at large Froude and Weber number
… key factor in controlling these processes is the size distribution of entrained bubbles. However, the underlying mechanisms/physics of air entrainment driven by free-surface turbulence (FST) and the resulted bubble size distribution still remain unclear. Therefore, detailed studies on air …
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An Investigation of the Gas Dispersion Properties of Mechanical Flotation Cells: an In-Situ Approach
Bubble size is considered to be one of the most important parameters affecting the performance of froth flotation cells. However, monitoring, controlling and predicting bubble size is a very challenging task. This dissertation presents results obtained from a comprehensive pilot- and …
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Hydrodynamics and gas dispersion in industrial flotation cells
… 40 industrial flotation cells of various types, sizes and duties in a Platinum Group Metal (pgm) concentrator in the North West Province of South Africa. The wide variety of cells studied included a Bateman 3-m³ cell, Outokumpu 16-m³ conventional and 50-m³ TankCells, WEMCO 84, 120, 144 cells and …
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Predicting Oxygen Transfer in Hypolimnetic Oxygenation Devices
… purpose of this research was to apply a discrete-bubble model to predict the performance of several hypolimnetic oxygenators. The model is used to predict the oxygen transfer rate in a hypolimnetic oxygenator based on the initial bubble size formed at the diffuser. The discrete-bubble model is …
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Análise experimental do efeito do ângulo de injeção de gás em um escoamento vertical ascendente de líquido
… in a upward vertical liquid flow, regarding the bubble size and shape distributions, as well as liquid velocity profile, both in the injection area. The experiments are carried in a 44 mm acrylic vertical pipe, in which water flows and air is injected through an angled device, in relation to the …
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Scale-up behavior of the froth stability measurement
… froth column diameter and initial pulp bubble size, was chosen to illustrate the dependence of the current methodology on scale. This does not mean that there are not vastly more parameters that would affect the measurement (column material of construction and/or column shape); however, …
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Rheological effects on gas dispersion in a pilot scale mechanical flotation cell
… dispersion is a primary requirement for particle-bubble contacting. Due to the mineralogical complexity of ores, it is required that particles be ground even finer to liberate valuable minerals. Mining operations tend to run flotation circuits at fairly high solids concentrations in order to …
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Computational fluid dynamics modelling of dissolved oxygen in oxidation ditches.
… contributions to knowledge are the effect of bubble size distribution (BSD) and biochemical oxygen demand (BOD) distribution on the DO distribution. Species transport modelling predicts the BOD and DO distribution in the ditch. De-oxygenation of local dissolved oxygen by BOD is modelled by an …
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Broadband acoustical scattering in coastal environments: application to gelatinous organisms
… acoustical techniques for characterizing microbubble populations have been established for decades, yet little is known about the spectral characteristics of dense microbubble clouds associated with estuarine tidal fronts. These bubbles facilitate air-sea gas exchange and could interfere with …
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The role of hydrocarbon oils in coal flotation : an investigation in to some pulp phase sub-processes
… selectivity), and the influence of oil on bubble creation and attachment were studied, in an attempt to explain observed differences in flotation behaviour with -500 μm unbeneficiated bituminous coal. Collectors were synthesis grade and commercial stocks of aromatic and aliphatic oils; MIBC …
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Broadband acoustical scattering in coastal environments: application to gelatinous organisms and gas microbubbles
… acoustical techniques for characterizing microbubble populations have been established for decades, yet little is known about the spectral characteristics of dense microbubble clouds associated with estuarine tidal fronts. These bubbles facilitate air-sea gas exchange and could interfere with …
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Formation, structure, and reproducibility of cerato-ulmin hydrophobin-coated bubbles
… characteristics of both the submicron and micron bubble films were investigated. For the submicron bubbles, small-angle x-ray scattering (SAXS) and small-angle neutron scattering (SANS) show the bubbles are cylindrical with a ~70 nm cross-sectional diameter and film thickness of 15 nm, the …
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Modeling of multiphase turbulent flow in continuous casting of steel
… these two paths is redistributed into small bubbles through complex gas redistribution processes, and the size distribution of the bubbles affects flow patterns as well as defect mechanisms in molds. Estimation of the exact amount of argon gas and size distribution of bubbles is crucial to …
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Effect of hydrophobicity and surface roughness on two-phase flow in rectangular microchannels
… applications involve the transport of bubbles in confined fluidic networks in channels of micrometer length scale. These types of two-phase flows result in pressure variations, leading to an overall increase in pressure drop. Among various flow parameters, pressure drop is extensively …
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Chemical transport by methane ebullition in a freshwater lake
… of this methane is released via bubbling. Bubbles dissolve as they rise, and the fraction of original methane that dissolves versus escapes to the atmosphere is strongly influenced by bubble size. While bubble sizes are critical to methane fate, traditional methods of measuring bubbles …
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